Remziye Güzel | Ankara University (original) (raw)

Papers by Remziye Güzel

Biosensors and Bioelectronics, Apr 1, 2018

Journal of Computational and Theoretical Nanoscience, Mar 1, 2012

Journal of The Electrochemical Society, 2013

Sensor Letters, Nov 1, 2014

ABSTRACT The voltammetric behavior of sildenafil citrate (SC) was studied through differential pu... more ABSTRACT The voltammetric behavior of sildenafil citrate (SC) was studied through differential pulse stripping voltammetry. The best sensitivity, optimal experimental conditions and settings for the voltammetric method development were obtained by applying experimental design and optimization methodology to the designed sample runs at different accumulation times, accumulation potentials and pHs. The linearity over the concentration range 1 × 10–7 M–8 × 10–6 M for SC was determined and the limit of detection (LOD) was 3.1 × 10–8 M. For the method ability and validity, mean recovery result and relative standard deviation were found to be 99.3% and 2.19%, respectively. The method was applied to the determination of SC in pharmaceutical and plasma samples.

Journal of Analytical Chemistry, Mar 1, 2019

Journal of Chromatographic Science, Jul 22, 2015

Electroanalysis, Nov 26, 2014

An electrochemical biosensor was developed for the determination of Escherichia coli (E. coli) in... more An electrochemical biosensor was developed for the determination of Escherichia coli (E. coli) in water. For this purpose, silver‐gold core‐shell (Ag@Au) bioconjugates and anti‐E. coli modified PS‐microwells were designed in a sandwich‐type format in order to obtain higher sensitivity and selectivity. Ag@Au bimetallic nanoparticles were synthesized by co‐reduction method. The core‐shell formation was analyzed by using UV‐Vis spectroscopy and transmission electron microscopy. Biotin labeled anti‐E. coli antibodies were coupled with Ag@Au nanoparticles to form bioconjugates. The electrochemical immunosensor was prepared by immobilizing anti‐E. coli on polystyrene (PS)‐microwells via chemical bonding. These modified microwells were identified with X‐ray photoelectron spectroscopy and surface enhanced Raman spectroscopy. E. coli was sandwiched between Ag@Au bioconjugates and anti‐E. coli on PS‐microwells at different concentrations. The relationship between the E. coli concentration and stripping current of gold ions (Au3+) were investigated by square wave anodic stripping voltammetry at pencil graphite electrode. The proposed method can provide some advantages such as lower detection limit and shorter detection time. The electrochemical response for the immunosensor was linear with the concentration of the E. coli in the range of 101 and 105 cfu/mL with a limit of detection 3 cfu/mL. The procedure maintains good sensitivity and repeatability and also offers utility in the fields of environmental monitoring and clinical diagnosis.

Journal of Computational and Theoretical Nanoscience, Oct 1, 2011

Journal of Food and Drug Analysis, Apr 1, 2017

Communications in Nonlinear Science and Numerical Simulation, Feb 1, 2012

Surface and Interface Analysis, Oct 7, 2013

ABSTRACT In this study, 4‐thiophenol modified glassy carbon electrode was prepared by the reducti... more ABSTRACT In this study, 4‐thiophenol modified glassy carbon electrode was prepared by the reduction of 4‐diazothiophenol tetrafluoroborate salt. Silver nanoparticles were attached to the thiophenol modified surface to prepare a thiophenol‐silver nanoparticle composite film. 4‐Aminothiopenol molecules were deposited by self‐assembling technique to form multi‐layered nanofilms of TP/SNP/PhNH2 on glassy carbon substrate. These surfaces were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, X‐ray photoelectron spectroscopy, reflectance‐absorption infrared spectroscopy, and ellipsometry at each multilayer film growth process. Atomic force microscopic images of GC/TP/SNP/PhNH2 surfaces were also acquired. The characterization methods show that the amine group containing surface permits the subsequent modification by a variety of coupling reactions for the immobilization of more complex systems. An application of the electrode modification for the determination of uric acid with a significantly lower detection limit is described. Copyright © 2013 John Wiley & Sons, Ltd.

Spectroscopy Letters, Mar 7, 2011

DergiPark (Istanbul University), May 1, 2014

In recent years, many types o f nanomaterials, especially metallic nanoparticles, have received g... more In recent years, many types o f nanomaterials, especially metallic nanoparticles, have received great attention due to their optical, physical, chemical and electrochemical properties [1]. Nowadays, core-shell bimetallic nanoparticles with different shell or core structure have important implications in enzyme-based sensors, DNA sensors and immunosensors [2]. Immunoassays have been vvidely used for the deteetion of target substances (antigens) at low concentrations and are based on the specific reaction o f antigen and antibody [3]. Electrochemical techniques such as anodic stripping voltammetry provide some advantages such as low ümit o f deteetion, high sensitivity and fast analysis time [4].

Journal of Chromatographic Science, 2021

In the presented work, a three-way analysis of ultra-performance liquid chromatography-photodiode... more In the presented work, a three-way analysis of ultra-performance liquid chromatography-photodiode array (UPLC-PDA) dataset was performed by parallel factor analysis (PARAFAC) for quantitatively resolving a ternary mixture containing paracetamol and methocarbamol with indapamide selected as an internal standard in their co-eluted chromatographic conditions. Paracetamol and methocarbamol were quantified in the working range between 3–24 and 5–50 μg/mL by applying PARAFAC decomposition to UPLC-PDA data array obtained under unresolved chromatographic peak conditions. To compare the experimental results provided by co-eluted UPLC-PARAFAC method, an ordinary UPLC method was developed ensuring proper separation of the peaks. The performance of both PARAFAC and ordinary UPLC methods were assessed by quantifying independent test samples, intra- and inter-day samples and spiked samples of pharmaceutical preparations. Then, both methods were applied for quantitative estimation of the related d...

Son yillarda, bircok arastirmaci monometalik turlerine kiyasla; optik, elektronik, katalitik, mag... more Son yillarda, bircok arastirmaci monometalik turlerine kiyasla; optik, elektronik, katalitik, magnetik vb. bircok ustun ozelliklerinden dolayi bimetalik nanoparcacik yapilarla yogun bir ilgi icerisindedirler. Bimetalik nanoparcacik yapisi iki elementin dagilimi seklinde; rastgele bir alasim olusumu, intermetalik bir bilesik ile alasim olusumu, kafes icinde kafes olusumu ve cekirdek-kabuk olusumu ile ifade edilebilir. Organik ya da inorganik bir materyalin kabuk olarak secilmesiyle, bir inorganik cekirdek nanoparcacigin etrafini kaplamasi sonucu elde edilen cekirdek-kabuk nanokompozit yapilarin sentezlenmesi son donemlerde incelenen konulardan birisidir. Ote yandan, hidrojeller yumusaklik, elastiklik ve sulu ortamda yuksek sisme kabiliyetleri nedeniyle buyuk olcude onem arz etmektedirler. Cevreleyen sividaki pH, sicaklik, basinc, elektriksel alan ve iyonik siddet gibi fiziksel ya da kimyasal sartlarin degisime karsin monomere bagli olarak uyari-cevap davranisi sergilerler.Surfaktansiz emulsiyon polimerlesmesi teknigi, cesitli monometalik nanoparcaciklarin hidrojelle kaplanmasi hususunda arastirmacilarin cogu tarafindan bilinen ve tercih edilen bir yontemdir. Bu calismada; literaturde bir ilk olarak; surfaktansiz emulsiyon polimerlesmesi teknigi ile p(NIPAm-ko-AAc) hidrojel kapli Aucekirdek@Agkabuk veya Agcekirdek@Aukabuk bimetalik nanokompozitlerin sentezlenmesi, spektroskopik (UV-vis, FT-IR, SERS); mikroskopik (SEM, TEM) ve elektrokimyasal (CV) metotlarla karakterize edilerek mikrobiyolojik E.Coli turune karsi antibakteriyel etkisinin ve sensor olarak kullaniminin arastirilmasi amaclanmistir.

Journal of The Electrochemical Society, 2013

Journal of Computational and Theoretical Nanoscience, 2011

Biosensors and Bioelectronics, Apr 1, 2018

Journal of Computational and Theoretical Nanoscience, Mar 1, 2012

Journal of The Electrochemical Society, 2013

Sensor Letters, Nov 1, 2014

ABSTRACT The voltammetric behavior of sildenafil citrate (SC) was studied through differential pu... more ABSTRACT The voltammetric behavior of sildenafil citrate (SC) was studied through differential pulse stripping voltammetry. The best sensitivity, optimal experimental conditions and settings for the voltammetric method development were obtained by applying experimental design and optimization methodology to the designed sample runs at different accumulation times, accumulation potentials and pHs. The linearity over the concentration range 1 × 10–7 M–8 × 10–6 M for SC was determined and the limit of detection (LOD) was 3.1 × 10–8 M. For the method ability and validity, mean recovery result and relative standard deviation were found to be 99.3% and 2.19%, respectively. The method was applied to the determination of SC in pharmaceutical and plasma samples.

Journal of Analytical Chemistry, Mar 1, 2019

Journal of Chromatographic Science, Jul 22, 2015

Electroanalysis, Nov 26, 2014

An electrochemical biosensor was developed for the determination of Escherichia coli (E. coli) in... more An electrochemical biosensor was developed for the determination of Escherichia coli (E. coli) in water. For this purpose, silver‐gold core‐shell (Ag@Au) bioconjugates and anti‐E. coli modified PS‐microwells were designed in a sandwich‐type format in order to obtain higher sensitivity and selectivity. Ag@Au bimetallic nanoparticles were synthesized by co‐reduction method. The core‐shell formation was analyzed by using UV‐Vis spectroscopy and transmission electron microscopy. Biotin labeled anti‐E. coli antibodies were coupled with Ag@Au nanoparticles to form bioconjugates. The electrochemical immunosensor was prepared by immobilizing anti‐E. coli on polystyrene (PS)‐microwells via chemical bonding. These modified microwells were identified with X‐ray photoelectron spectroscopy and surface enhanced Raman spectroscopy. E. coli was sandwiched between Ag@Au bioconjugates and anti‐E. coli on PS‐microwells at different concentrations. The relationship between the E. coli concentration and stripping current of gold ions (Au3+) were investigated by square wave anodic stripping voltammetry at pencil graphite electrode. The proposed method can provide some advantages such as lower detection limit and shorter detection time. The electrochemical response for the immunosensor was linear with the concentration of the E. coli in the range of 101 and 105 cfu/mL with a limit of detection 3 cfu/mL. The procedure maintains good sensitivity and repeatability and also offers utility in the fields of environmental monitoring and clinical diagnosis.

Journal of Computational and Theoretical Nanoscience, Oct 1, 2011

Journal of Food and Drug Analysis, Apr 1, 2017

Communications in Nonlinear Science and Numerical Simulation, Feb 1, 2012

Surface and Interface Analysis, Oct 7, 2013

ABSTRACT In this study, 4‐thiophenol modified glassy carbon electrode was prepared by the reducti... more ABSTRACT In this study, 4‐thiophenol modified glassy carbon electrode was prepared by the reduction of 4‐diazothiophenol tetrafluoroborate salt. Silver nanoparticles were attached to the thiophenol modified surface to prepare a thiophenol‐silver nanoparticle composite film. 4‐Aminothiopenol molecules were deposited by self‐assembling technique to form multi‐layered nanofilms of TP/SNP/PhNH2 on glassy carbon substrate. These surfaces were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, X‐ray photoelectron spectroscopy, reflectance‐absorption infrared spectroscopy, and ellipsometry at each multilayer film growth process. Atomic force microscopic images of GC/TP/SNP/PhNH2 surfaces were also acquired. The characterization methods show that the amine group containing surface permits the subsequent modification by a variety of coupling reactions for the immobilization of more complex systems. An application of the electrode modification for the determination of uric acid with a significantly lower detection limit is described. Copyright © 2013 John Wiley & Sons, Ltd.

Spectroscopy Letters, Mar 7, 2011

DergiPark (Istanbul University), May 1, 2014

In recent years, many types o f nanomaterials, especially metallic nanoparticles, have received g... more In recent years, many types o f nanomaterials, especially metallic nanoparticles, have received great attention due to their optical, physical, chemical and electrochemical properties [1]. Nowadays, core-shell bimetallic nanoparticles with different shell or core structure have important implications in enzyme-based sensors, DNA sensors and immunosensors [2]. Immunoassays have been vvidely used for the deteetion of target substances (antigens) at low concentrations and are based on the specific reaction o f antigen and antibody [3]. Electrochemical techniques such as anodic stripping voltammetry provide some advantages such as low ümit o f deteetion, high sensitivity and fast analysis time [4].

Journal of Chromatographic Science, 2021

In the presented work, a three-way analysis of ultra-performance liquid chromatography-photodiode... more In the presented work, a three-way analysis of ultra-performance liquid chromatography-photodiode array (UPLC-PDA) dataset was performed by parallel factor analysis (PARAFAC) for quantitatively resolving a ternary mixture containing paracetamol and methocarbamol with indapamide selected as an internal standard in their co-eluted chromatographic conditions. Paracetamol and methocarbamol were quantified in the working range between 3–24 and 5–50 μg/mL by applying PARAFAC decomposition to UPLC-PDA data array obtained under unresolved chromatographic peak conditions. To compare the experimental results provided by co-eluted UPLC-PARAFAC method, an ordinary UPLC method was developed ensuring proper separation of the peaks. The performance of both PARAFAC and ordinary UPLC methods were assessed by quantifying independent test samples, intra- and inter-day samples and spiked samples of pharmaceutical preparations. Then, both methods were applied for quantitative estimation of the related d...

Son yillarda, bircok arastirmaci monometalik turlerine kiyasla; optik, elektronik, katalitik, mag... more Son yillarda, bircok arastirmaci monometalik turlerine kiyasla; optik, elektronik, katalitik, magnetik vb. bircok ustun ozelliklerinden dolayi bimetalik nanoparcacik yapilarla yogun bir ilgi icerisindedirler. Bimetalik nanoparcacik yapisi iki elementin dagilimi seklinde; rastgele bir alasim olusumu, intermetalik bir bilesik ile alasim olusumu, kafes icinde kafes olusumu ve cekirdek-kabuk olusumu ile ifade edilebilir. Organik ya da inorganik bir materyalin kabuk olarak secilmesiyle, bir inorganik cekirdek nanoparcacigin etrafini kaplamasi sonucu elde edilen cekirdek-kabuk nanokompozit yapilarin sentezlenmesi son donemlerde incelenen konulardan birisidir. Ote yandan, hidrojeller yumusaklik, elastiklik ve sulu ortamda yuksek sisme kabiliyetleri nedeniyle buyuk olcude onem arz etmektedirler. Cevreleyen sividaki pH, sicaklik, basinc, elektriksel alan ve iyonik siddet gibi fiziksel ya da kimyasal sartlarin degisime karsin monomere bagli olarak uyari-cevap davranisi sergilerler.Surfaktansiz emulsiyon polimerlesmesi teknigi, cesitli monometalik nanoparcaciklarin hidrojelle kaplanmasi hususunda arastirmacilarin cogu tarafindan bilinen ve tercih edilen bir yontemdir. Bu calismada; literaturde bir ilk olarak; surfaktansiz emulsiyon polimerlesmesi teknigi ile p(NIPAm-ko-AAc) hidrojel kapli Aucekirdek@Agkabuk veya Agcekirdek@Aukabuk bimetalik nanokompozitlerin sentezlenmesi, spektroskopik (UV-vis, FT-IR, SERS); mikroskopik (SEM, TEM) ve elektrokimyasal (CV) metotlarla karakterize edilerek mikrobiyolojik E.Coli turune karsi antibakteriyel etkisinin ve sensor olarak kullaniminin arastirilmasi amaclanmistir.

Journal of The Electrochemical Society, 2013

Journal of Computational and Theoretical Nanoscience, 2011